In a traditional cell phone architecture, cell towers communicate with each of the phones in their broadcast region. The cell towers determine, based on a variety of factors, which power level each cell phone should use when communicating with that cell tower. Ideally, each phone will use the minimum amount of power possible so that the various phones' signals don't interfere with each other. Indeed, if one phone is transmitting at a very high power rate in a certain area, that phone's transmission signal can cause interference with other phone's signals.
In mobile ad hoc networks, each node may be configured to use substantially the same amount of power when transmitting a signal. However, in cases where the nodes are mobile (such as cars, airplanes, or passengers with mobile phones), some nodes may be physically much closer to each other than others. In such cases, those nodes will continue to transmit data to each other at a high power level. This high power level can cause interference in the mobile ad hoc network.
Moreover, many data networks use data bursting to transmit large amounts of data in a small amount of time. When bursting data, a phone or other device uses a comparatively large amount of power to transmit data at a higher rate for a short amount of time. Data bursting, however, depletes battery power quickly, and requires a larger antenna. Battery life and hardware component space on mobile devices are already scarce commodities, and data bursting only makes the problem worse.
Traditional cell towers allow multiple devices to simultaneously transfer these data bursts using some form of multiple access technology. Code division multiple access (CDMA) is one form of multiple access. In CDMA, each device transmits on the same frequency at the same time, but each device has a separate code. The cell tower chooses which code(s) to listen to at any given time. In time division multiple access (TDMA), each device take turns transmitting data on the same frequency according to a synchronized clock, each transmitting during its specified time. Frequency division multiple access (FDMA) provides each device with its own frequency band and the device transmits and receives in that band.